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At the present time, machines employed for the production of mechanical energy by internal combustion of organic fuel consist primarily of mechanical displacement reciprocating engines and gas turbines.
Reciprocating engines employ reciprocating pistons and valves to accomplish working fluid manipulation and fuel combustion occurs as a periodic process. The functional principles of the reciprocating internal combustion engine are described in terms of the theoretical thermodynamic cycle postulated by Sadi Carnot in 1824 or in terms of one of the theoretical thermodynamic cycles subsequentially postulated by Nicholas Otto in 1876 and Rudolph Diesel in 1892. Gas turbines employ purely rotational aerodynamically interacting components to accomplish working fluid manipulation and fuel combustion is a self-sustaining continuous process. In general, gas turbines theoretically function in accordance with a thermodynamic cycle as postulated by G. B. Breyton in 1876.
Reciprocating engines are economically satisfactory power sources for many commercial applications but are mechanically complex and the reciprocating components and the periodic combustion process are inherent sources of undesirable noise and vibration. In comparison, gas turbine machines characteristically offer the attributes of relatively higher power density and reduced emissions of noise and vibration but offer economic superiority only in applications requiring relatively high measures of delivered power.
Over a number of years significant inventive effort has been directed toward the derivation of a xe2x80x9crotaryxe2x80x9d internal combustion machine that give the performance characteristics of reciprocating engines but preclude their concomitant mechanical complexity and potential for emission of noise and vibration. The radial vane type rotary machine has been the subject of particular attention in this regard.
Conceptually the rotary vane machine primarily consists of a stationary housing containing a rotationally dynamic mechanical assembly. The stationary housing consists of a containment cylinder installed with end closure structures and ports for movement of combustion air and combustion products through the structural boundary. The rotationally dynamic mechanical assembly primarily consists of a rotational armature and a set of radial vanes. Said rotational armature is precisely or approximately circular in cross section and is concentrically secured on a rotational shaft. Said rotational shaft is constrained by rotational bearings with its rotational axis parallel to but radially displaced from the bore axis of said containment cylinder and its axial ends are configured to interface with external rotational power machines. Said rotational armature is proportioned to have an effective diameter significantly less than the bore diameter of said containment cylinder in order to create an annular space around its periphery. Said rotational armature is fitted with a number of axially oriented radial vane slots equally distributed around its periphery. Each radial vane slot accommodates and provides annular sliding support for one radial vane. Each said radial vane is proportioned to axially extend through the axial length of said rotational armature and radially extend from within said radial vane slot to the bore of said containment cylinder. The set of radial vanes thus subdivides the annular space surrounding said rotational armature into a number of segmental chambers. Since the rotational axis of said rotational armature is radially displaced from the bore axis of said containment cylinder, the relative volume of any said segmental chamber is dependent upon its orbital location and is cyclically changed through rotation of said rotational armature. The dynamic relationship between rotational armature rotation and relative segmental chamber volume is functionally analogous to the relationship between relative cylinder volume and crankshaft rotation as occurs in reciprocating type internal combustion machines and provides the working fluid manipulation features necessary for evolution of a Carnot type heat engine cycle. For a given set of containment cylinder proportions, the manipulated volume is inversely influenced by the diameter of said armature. Within certain limits, the effective compression ratio of the volumetric cycle is directly influenced by both the number of segmental chambers surrounding said rotational armature and the distance separating the rotational axis of said rotational armature from the bore axis of said containment cylinder. Said effective compression ratio is also influenced by the angular width and orbital location of the sectors allocated for the combustion air supply port and for the combustion product discharge port.
A number of patents have been awarded for rotary vane internal combustion machine concept but, despite the potentially excellent qualities offered by the machine, none of the concepts presented in prior art are known to have matured sufficiently to demonstrate practical utility. It is hypothesized that such non-maturation is the result of singular or compounded inadequacies regarding the functional viability of the perceived entities. As known to persons skilled in the art, the fundamental functional viability of all machines is dependent upon their compatibility with natural laws related to physics, mathematics, and chemistry. It is also known that the functional viability of an energy related machine is dependent upon its capability to meet thresholds for overall efficiency and reliability within constraints imposed by economic considerations. Overall efficiency of a thermal machine is critically dependent upon attaining certain minimum thresholds for both thermodynamic cycle efficiency and mechanical efficiency and functional reliability is critically dependent upon maintaining component temperatures within thresholds prescribed by material characteristics. For these reasons the potential functional viability of a thermal machine may be assessed by analytical review of its functional geometry and component features relative to heat cycle efficiency, mechanical efficiency, and thermal management considerations.
For internal combustion machines based on Carnot principles and with numerically equal compression and expansion ratios, the basic relationship between cycle efficiency (xe2x80x9cAir Standard Efficiencyxe2x80x9d) and the effective compression ratio is:             η      c        =          1      -              1                  v                      (                          κ              -              1                        )                                    Where    ⁢          :                                                η            c                    =                      Cycle            ⁢                          xe2x80x83                        ⁢            Efficency                                                        v          =                      Effective            ⁢                          xe2x80x83                        ⁢            Compression            ⁢                          xe2x80x83                        ⁢            Ratio                                                        k          =                      Universal            ⁢                          xe2x80x83                        ⁢            Gas            ⁢                          xe2x80x83                        ⁢            Constant                              
The relationship shown above demonstrates that heat cycle efficiency is favorably influenced by the magnitude of the compression ratio accomplished within the volumetric manipulation. As previously noted, the effective compression ratio of a rotary vane machine is directly influenced by the number of the annular segmental chambers surrounding the armature and the distance between the rotational armature axis and containment cylinder bore axis. Analysis demonstrates that the threshold for adequate cycle efficiency is attained only if the number of segmental chambers surrounding the rotational armature and the distance between the rotational armature axis and containment cylinder bore axis both exceed certain minimum values.
Mechanical efficiency is essentially the measure of mechanical energy conservation exhibited by a mechanism in the process of doing work. Mechanical efficiency is adversely influenced by the quantity of energy dissipated by frictional interaction between dynamically interfacing components and in this context may simply be expressed as:             η      m        =                            P          i                -                  P          f                            P        i                  Where    ⁢          :                                                η            m                    =                      Mechanical            ⁢                          xe2x80x83                        ⁢            Efficency                                                                    P            i                    =                      Input            ⁢                          xe2x80x83                        ⁢            Power                                                                    P            f                    =                      Power            ⁢                          xe2x80x83                        ⁢            Consumed            ⁢                          xe2x80x83                        ⁢            by            ⁢                          xe2x80x83                        ⁢            Internal            ⁢                          xe2x80x83                        ⁢            Friction                              
Power consumed by internal friction is the sum of the increments of power consumed by individual frictional components. In radial vane type rotary machines the radial vanes create the preponderance of the dynamically active mechanical interfaces and are, thereby, a particularly significant potential cause of power loss due to friction. Potential friction sources are; a) peripheral edge friction caused by sliding contact of said radial vanes with bore of the stationary containment cylinder, b) axial end friction caused by sliding contact of axial ends of the radial vanes with non-rotating end closure components, and c) radial friction caused by sliding contact of the faces of radial vanes with the supporting surfaces of rotational armature. The magnitude of energy loss due to friction is also significantly influenced by the nature of the materials in sliding contact and the effectiveness of lubrication at the contact surface. Analysis demonstrates that without deliberate friction reduction the number of radial vanes necessary to achieve functional viability from a thermodynamic cycle efficiency viewpoint could, alone, incur sufficient friction to cause the machine to be non-viable from a mechanical efficiency viewpoint.
Internal combustion machine components are exposed to heat from three sources, adiabatic compression, fuel combustion, and friction. Component temperature must be constrained with certain thresholds in order to avoid performance degradation through thermal expansion, strength reduction, or lubricant failure. For these reasons the functional viability of internal combustion machines is dependent upon adequate thermal control. Thermal control normally consists of the movement of liquid and/or gaseous heat extraction media across component surfaces and, in general, the rate of heat extraction is directly influenced by both the surface area and flow rate of heat extraction media. Thermal control for stationary enclosures is readily accomplished by exposure of external surfaces to ambient air or by movement liquid heat extraction media through integral passageways. Thermal control for internal mechanically dynamic components is normally accomplished by circulation of air and liquid lubricant. In the case of reciprocating machines the internal mechanically dynamic components are substantially isolated from high temperature working fluid and they are conveniently exposed to internal thermal control media contained within a stationary crankcase. In comparison the internal mechanically dynamic components of rotary vane machines are relatively more substantially exposed to contact with high temperature working fluid and significantly less conveniently exposed to thermal control media. For these reasons the means for maintaining internal thermal control is a vital issue regarding the functional viability of rotary vane thermal machines.
Rotary vane machine disclosures presented to date substantially focus on technical approaches toward minimization of friction and in particularly friction related to the relative motion between the radial vanes and the bore of the containment cylinder but, in general, they are substantially silent regarding the other functional viability issues discussed above. Principal features of several relevant prior disclosures are briefly reviewed below.
U.S. Pat. No. 2,590,132 discloses a rotary vane machine in which each radial vane is radially constrained by cylindrical extensions at each axial end one of which engages a rotating ring and the other engages a rotating disk. An annular cylinder is coaxially secured to both said rotating ring and said rotating disk and is axially and radially constrained by a rotational bearing installed in a stationary structure at one axial end. Said annular cylinder is installed with axially aligned radial slots with each slot proportioned to accommodate and permit radial movement of one said radial vane and with axially aligned sealing strips secured on its outer periphery and proportioned to maintain sliding contact with the bore of a stationary housing. Each said radial vane is radially constrained to maintain a small distance between its radially outermost axial edge and the bore of said stationary housing. A spring loaded sliding seal is installed on the radially outermost axial edge of each said radial vane and proportioned to maintain pressure contact with the bore of said stationary housing. Lubrication and thermal control issues are not discussed.
U.S. Pat. No. 5,568,796 discloses an independent vane rotary machine in which each radial vane is radially constrained by pivotal bearings installed on a rotating hub. Each said radial vane is radially proportioned to extend through a rotating circular annulus installed on rotational bearings and aligned with its rotational axis parallel to but separate from the rotational axis of said hub. Gears maintain said hub and said circular annulus in synchronous rotation. The bore of said stationary housing is contoured and each said radial vane is proportioned to maintain a constant distance of separation between the radially outermost axial edge of said radial vane and the bore of said stationary housing. A seal is installed on the outermost axial edge of each said radial vane to close the gap between said radial vane and the bore of said stationary housing. The disclosure demonstrates that one said assembly fulfills the functional requirements of a gaseous fluid compressor and also demonstrates that two such assemblies mechanically coupled can collectively fulfill the functional requirements of a heat engine cycle. The disclosure is silent regarding means for sealing the axial ends of segmental chambers, centrifugal restraint of vane edge seals and issues related to lubrication and thermal control for internal components.
U.S. Pat. No. 5,709,188 discloses an independent vane rotary machine in which each radial vane is radially constrained by a mechanical link installed on its radially innermost axial edge and radially extends through a rotational annulus. Said rotational annulus is aligned with its rotational axis parallel to but separate from the bore of a stationary housing. A stationary cam is axially secured at one axial end of the stationary housing. Rotational motion of said rotational annulus causes interaction of said stationary cam and said mechanical link to induce cyclical radial movement of said radial vane. The bore of said stationary housing is contoured and each said radial vane is proportioned to maintain a constant distance of separation between the radially outermost axial edge said radial vane and the bore of said stationary housing. A seal is installed on the radially outermost axial edge of each said radial vane and radially constrained by direct contact with the bore of said stationary housing. The disclosure demonstrates that two such assemblies rotationally coupled can collectively fulfill the functional requirements of a heat engine cycle. The disclosure presents an approach for lubrication by centrifugally induced circulation of liquid media but is silent regarding means for closing the axial ends of segmental chambers and means for thermal control for internal components.
U.K. Pat. No. 468,390 presents improvements in and relating to rotary piston machines and features uninterrupted combustion of fuel at constant pressure, combustion of different fuel types and control by throttle like devices. The disclosure also demonstrates that two rotary vane machines may be non-mechanically coupled to collectively fulfill the four functional phases of a heat engine cycle. Disclosure drawings illustrate a rotary device consisting of a stationary containment cylinder, a rotational shaft and a solid rotor fitted with six radial vane slots and six radial vanes. The disclosure is silent regarding issues related to lubrication, thermal control and other functional viability considerations.
U.S. Pat. No. 6,024,549 discloses an independent vane rotary machine in which each radial vane is accommodated within a radial slot installed in a rotational annulus and each axial end of each said radial vane is radially constrained by an axially extended flange installed on the outer periphery of a rotating disk. Each said rotating disk is diametrically proportioned to closely approach a circular bore in a stationary containment cylinder and radially constrains said radial vane to maintain a constant distance between the radially outermost axial edge of said radial vane and said containment cylinder bore. A seal is installed on the outer axial edge of each said radial vane resiliently closes the gap between said radial vane and said containment cylinder bore. An axially extending compression spring is installed at each axial end of the rotational assembly. Each said axially extending compression spring is proportioned to induce resilient axial contact of its contiguous said rotating disk and the axial end of said rotational annulus and thus close the axial ends of segmental chambers but accommodate variations in component geometry caused by thermal expansion or mechanical loading. Disclosure includes a system for dispersion of thermal control and lubricant media within said rotational annulus and for extraction of condensate and excess lubricant.
U.S. Pat. No. 6,349,695 discloses an independent rotary vane rotary machine in which each radial vane is radially constrained by radial vane retainer concentrically secured on a rotational shaft. Each said radial vane is accommodated within a radial slot installed in a rotational annulus. Each said radial slot in said rotational annulus additionally accommodates and annularly constrains one pair of radially extending compression springs. Said radially extending compression springs are constrained and proportioned to resiliently maintain said rotational annulus and said rotational shaft in synchronous rotation. An articulated radial vane extension is installed between each said radial vane and said radial vane retainer and each said articulated radial vane extension is proportioned to maintain a constant distance between the outer axial edge of each said radial vane and the circular bore of a stationary containment cylinder. A seal installed on the outer axial edge of each said radial vane is proportioned to resiliently close the gap between the outer axial edge said radial vane and the bore of said stationary housing. One rotating disk diametrically proportioned to closely approach the bore of said stationary containment cylinder is installed at each axial end of said rotational annulus and one axially extending compression spring is installed at each axial end of the rotational assembly. Said axially extending compression spring is proportioned to induce the contiguous said rotating disk to make resilient axial contact with the axial end of said annulus and thus close the axial ends of segmental chambers but accommodate variations in component geometry caused by thermal expansion or mechanical loading. Disclosure includes a system for the movement of thermal control and lubricant media within said rotor annulus and for extraction of excess lubricant.
It is believed that none of the above disclosures taken singly or combination describes the form and functional features of the invention presented in this disclosure.
This disclosure presents a rotary vane internal combustion machine for efficient production of rotational mechanical energy through internal combustion of liquid or gaseous fuel. The machine functions in general accordance with the principles of the Carnot heat engine cycle but mechanical manipulation of working fluid is accomplished without the use of reciprocating components and combustion is performed as a continuously sustained process. The machine primarily consists of a stationary containment and foundation structure and an internal rotationally dynamic mechanical assembly.
The stationary containment and foundation structure consists of a containment cylinder with circular bore installed with a closure structure at each axial end. Ports for induction of combustion air and discharge of combustion products are mutually interspersed throughout the axial length of said containment cylinder and are peripherally dispersed and radially oriented to minimize their collective sector width and to symbiotically promote their functional efficiency. Additional ports are also installed as required for induction of fuel, externally supplied ignition energy, and internal thermal control and lubrication media, and for maintaining continuous internal combustion.
The internal rotationally dynamic assembly primarily consists of one rotational armature, one rotational shaft, a synchronizing gear set, and a set of radial vanes. Said rotational armature features a circular cross section proportioned with an outside diameter equal to approximately eighty five percent of the bore of said containment cylinder and is configured as a structural annulus. Said rotational armature is fitted with a number of axial radial vane slots uniformly distributed around its periphery with each said radial vane slot extending through its axial length and through its annulus thickness. Said rotational armature is simply supported by one low friction rotational bearing installed at each axial end and is aligned with its rotational axis parallel to but radially separated from the bore axis of said containment cylinder. Said rotational shaft axially passes through said rotational armature and a low-friction rotational bearing installed in each said end closure structure. Said rotational shaft is aligned to rotate on an axis parallel to but radially separated from the rotational axis of said rotational armature. The axial ends of said rotational shaft are configured as necessary to mechanically interface with external rotary power devices. A radial vane retainer is concentrically secured on said rotational shaft within said rotational armature.
Said synchronizing gear set maintains a fixed rotational relationship between said rotational armature and said rotational shaft. One main synchronizing gear is secured on one axial end of said rotational armature and one main synchronizing gear is adjacently secured on said rotational shaft. Both said rational armature main synchronizing gear and said rotational shaft main synchronizing gear are identical in pitch diameter and pitch. Said rational armature main synchronizing gear intermeshes with a peripheral rotational armature auxiliary synchronizing gear and said rotational shaft main synchronizing gear intermeshes with a peripheral rotational shaft auxiliary synchronizing gear. Both said rotational armature auxiliary synchronizing gear and said rotational shaft auxiliary synchronizing gear are identical in pitch diameter and pitch and share a common rotational axis. Said rotational armature auxiliary synchronizing gear and said rotational shaft auxiliary synchronizing gear are mechanically interlocked in the phase relationship necessary to maintain the appropriate rotational alignment of said rotational armature and said rotational shaft.
Each said radial vane slot accommodates one radial vane. Each said radial vane is free to radially slide between two axially aligned bearing surfaces. Each said radial vane is radially constrained by an articulated radial vane extension secured to its inner axial edge and secured to the outer periphery of said radial vane retainer. The radial extent of each said radial vane and each said articulated radial vane extension are proportioned to maintain a small gap between the outer axial edge of said radial vane and the bore of said containment cylinder. A mechanical radial vane edge seal is installed on the outer axial edge of each said radial vane to resiliently close the gap between said radial vane and the bore of said containment cylinder.
A freely rotating disk and axially extending compression spring are installed at each end of said rotational armature. Each said axial compression spring is proportioned to induce the axial face of its associated freely rotating disk to maintain axial contact with one axial end of said rotational armature to close the axial ends of segmental chambers, axially constrain the radial vanes, and resiliently accommodate variations in component geometry caused by thermal expansion and/or mechanical loading.
The internal axial cavity in said rotational armature is contoured to enlarge the surface area exposed to thermal control media and, hence, facilitate internal thermal control. Ports installed in said end closure structures and appropriate internal rotational components facilitate the axial movement of internal thermal control and lubrication media.
Necessary ancillary support items consist of an air supply fan, a fuel delivery system, an externally powered rotational device to initiate machine rotation, an electrically powered igniter to initiate combustion, and a lubricant management system.
The drawings presented in this disclosure illustrate the primary geometric and component features appropriate to obtaining the measures of thermodynamic efficiency, mechanical efficiency, and thermal control necessary for demonstration of functional viability.